This treatise, written on ten folio pages for an Ottoman official and patron of books known as Ismā‘īl Afandī, is on the inter-conversion of units of measurement. It is a useful guide for merchants and others engaged in the measurement of quantities. It provides instructions for converting arṭāl (plural of raṭl) into uqaq (plural of auqiya), and back; darāhim (plural of dirham) into mathāqīl (plural of mithqāl) and back; and converting the number of Ottoman (referred to as Roman, rūmī) loading bags into the number of Egyptian loading bags ...